I. Field of the Invention
This invention relates to a medical appliance for the treatment of a portion of body vessel by ionizing radiation, comprising a radioactive radiation means, and manipulation means.
Endoluminal brachytherapy and more particularly percutaneous transluminal brachytherapy currently face difficulties for handling, energizing, transporting and sterilizing the equipment used for applying the therapy.
II. Discussion of the Prior Art
For example, U.S. Pat. No. 5,147,232 discloses a manual irradiation loading apparatus particularly suitable for intrabronchial and gynecological irradiation treatment. The apparatus comprises a lead or equivalent radiation shielding body with a longitudinally extending cable-receiving passage therein. A cable having radioactive seeds provided on one end thereof is received in the cable-receiving passage. During storage, the portion of the cable bearing the radioactive source is located in the cable-receiving passage within the shielding body. During use, a catheter placed in a patient is joined to the shielding body and the portion of the cable bearing the radioactive source material is advanced through the cable receiving passage in the shielding body and into the catheter. The disclosure provides for using commercially available cable having radioactive seeds provided on an end portion thereof or radioactive wire.
According to one embodiment, this document provides for a shielding body constructed to receive a radiation source other than a seeded cable. A shielding body is therefore constructed with a metallic tube running therein from end to end, extending through one end of the shielding body and extending through and beyond the other end thereof. This metallic tube is for allowing free passage of a plastic tandem closed at one end and containing Cesium tube sources maintained in the tandem by a plastic stopper insert. For loading the radiation sources into the patient, an empty metal tandem is positioned in the patient and a docking tube with quick release connectors of the spring clip type with actuating levers at both ends is attached, one end to the shielding body and the other end to the patient""s metal tandem. Then, using a loading-retrival cable assembly, the plastic tandem containing the radioactive sources and the stopper insert is pushed through the shielding body via the docking tube and into the metal tandem inserted into the patient. The empty shielding body and the docking tube may then be temporarily removed and stored nearby.
When the irradiation treatment has been completed, the radioactive sources must be removed by means of the loading-retrival cable assembly. To this effect, the stopper insert is first removed from the plastic tandem and the docking tube and shielding body are again connected to the patient. To remove the radioactive sources the loading-retrival cable assembly comprises a steel cable surrounded by a teflon tube, this steel cable being terminated by a solid tip extending out of the teflon tube and bearing against a soft rubber ring located between the solid tip and the end of the teflon tube; the other end of the steel cable is attached to a retracting mechanism comprising a return spring urging the end of the steel cable and controlled by a set screw with eccentic lock-up. Within this configuration, the loading-retrival cable assembly is advanced through the shielding body and docking tube and stopped at the opening of the plastic tandem containing the radioactive sources and the cable solid tip and soft rubber ring and passed inside the plastic tandem. The set screw of the retracting mechanism is triggered to retract the steel cable thereby forcing the solid tip to squeeze the soft rubber ring against the end of the teflon tube so that the soft rubber ring expands radially and firmly gripe the inner wall of the plastic tandem. The loading-retrival cable assembly being thus connected to the plastic tandem containing the radioactive sources, one may pull the cable out of the docking tube and retrieve the plastic tandem and radioactive sources back to storage position inside the shielding apparatus. Reverse operation of the retracting mechanism disconnects the steel cable from the plastic tandem and the stopper insert maybe re-inserted into the plastic tandem.
In the case of usage of radioactive guidewires, there is the problem to safely secure the radioactive radiation source to the manipulating wire. The source can of course only be made of radiating material and will therefore always have only certain limited material properties. Another problem is that the source always has to be activated for itself without the manipulation wire. An activation together with the manipulation wire would also activate the wire, which would result in harmful radiation from the wire.
It is an object of this invention to improve the conditions of handling, energizing, transporting end sterilizing the materials used for endoluminal and more particularly percutaneous transluminal brachytherapy. It is a further object of the invention to improve such conditions by means of appliances that are simple to manufacture and easy to use. Still a further object of the invention is an equipment that is safe and devoid of hazardous structures, and which allows treatment in remote locations and narrow vessels.
To this effect, the invention complies with the definitions given in the claims.
Accordingly, the part of the radioactive radiation means making part of a detachable interlocking engagement between the radioactive radiation means and the manipulation means allows the manufacture of a tolerance free assembly which can be used without particularly precise or skill demanding manipulations. It also allows the realization of a place saving assembly capable of being inserted into very narrow vessels. And as it is not dependent on any mechanism it can be safely used for treatment of remote locations. The radioactive radiation means can be easily energized and handled separately from the advancing and removing means, whereby a simple and safe circulation of radioactive materials may be organized between the hospital and the energizing center or the manufacturer. In addition, as the radioactive radiation means may be handled alone, there is a substantial place saving in the energizing reactor, whereby a better and cheapest organization of the occupation of the reactor. In parallel, sterilization of the manipulation means can be achieved conventionally and without any particular shielding, while sterilization of the radioactive radiation means is systematically asured by the radioactive radiation. The invention thus solves the aforesaid problems by proposing a detachable connection between radiation source and manipulation wire which is formed by the radiation source itself. With this solution no complicated welding or other manipulation of the activated source is necessary. And as the radiation source can be activated for its own, separated from the manipulating wire, only the desired radiation is generated in purity.
Where the medical appliance comprises proximal recess means and stone means on the radioactive radiation means for cooperation with distal recess means and stone means arranged on the manipulation means, an assembly is achieved which allows selection at will of any desired longitudinal play in the assembly to combine a good pushability of the system with an appreciable capacity to handle narrow and tortuous vessels. And this interlocking engagement may be locked by mere insertion into a lumen.
The medical appliance may comprise proximal and distal wall means on the radioactive radiation means for cooperation with distal recess means arranged on the manipulation means, thereby achieving a detachable interlocking engagement which requires a very simple shaping of the radioactive radiation means and of the manipulation means. This interlocking engagement may also be locked by engagement into a lumen.
Where the appliance comprises proximal coil means on the radioactive radiation means for meshing with distal thread means on the manipulation means, a playless assembly is achieved which combines extreme flexibility and good pushability in a fully positive assembly which can be designed to reach the smallest dimensions.
In the case of the medical appliance comprising proximal recess means and store means, reap. proximal and distal wall means, on the radioactive radiation means for cooperation with distal recess means and stone means, resp. distal recess means, on the manipulation means, the detachable interlocking engagement may be locked by insertion into a lumen which may extend longitudinally into a catheter, whereby safest and fastest positioning of the radioactive radiation means may be achieved into the body vessel. In the case of the medical appliance comprising proximal coil means for meshing with distal thread means of the manipulation means, the detachable interlocking engagement may be guided by insertion into a lumen which may also extend longitudinally into a catheter, thereby facilitating meshing of the thread means into the coil means if the latter have a great flexibility. And in both cases, the medical appliance further may comprise a shielding applicator means for supporting the radioactive radiation means in its orientation towards the manipulation means, thereby allowing an operator to lock the detachable interlocking engagement between the radioactive radiation means and the manipulation means by manipulating the manipulation means. This shielding applicator means also facilitates transport and circulation of the radioactive radiation means.
These and other objects of the invention will become readily apparent from the following detailed description with reference to the accompanying drawings which show, diagrammaticaly and by way of example only, embodiments of the invention.